The invention relates generally to organophosphorous compounds, and more particularly, to organophosphorous compounds for synthesizing amino-derivatized polymers, especially oligonucleotides.
Genes and gene control regions can now be routinely characterized and studied at the molecular level. This is possible because of several recent advances in the technology associated with manipulating and modifying deoxyribonucleic acid (DNA). Of particular importance have been advances in DNA sequencing, Maxam and Gilbert, "Sequencing End-Labeled DNA with Base-Specific Chemical Cleavages," and Smith, "DNA Sequence Analysis by Primed Synthesis," pgs. 499-560 and 560-580, respectively, in Methods in Enzymology, Grossman and Moldave, eds., Vol. 65 (Academic Press, New York, 1980); the isolation of a large number of host restriction modification enzymes, Roberts, "Dictionary of Restriction Endonucleases," in Methods in Enzymology, Wu, ed., Vol. 68 (Academic Press, New York, 1979); and the construction of vectors for cloning and amplifying defined DNA sequences, e.g. Bolivar and Backman, "Plasmids of Escherichia coli as Cloning Vectors," in Methods in Enzymology, Wu, ed., Vol. 68 (Academic Press, New York, 1979).
Many of these new techniques require that DNA fragments or oligonucleotides be labeled or attached to polymer supports. DNA sequencing techniques and gene probes, which can be used to help locate natural genes of commercial or scientific importance, require the use of labeled oligonucleotides. Until recently, all DNA sequencing techniques relied on radioactive labels for distinguishing oligonucleotide fragments separated by electrophoresis. Radioactive labels are highly sensitive, and can be incorporated without steric hinderance, or other chemical side effects. However, their use poses a laboratory health hazard, which requires that they receive special handling and disposal. Moreover, their use is not amenable for rapid automatic sequencing of oligonucleotides, as nucleoside-specific radioactive labels are not available for practical identification of different nucleotide bases, and radiation detection techniques such autoradiography and scintillation counting are too time consuming. As a consequence, other non-radioactive labelingtechniques have been sought, such as fluorescent and colorimetric labeling, which depend on the ability to covalently link a fluorescent or chromogenic molecule to an oligonucleotide.
Chu et al, in "Derivatization of Unprotected Polynucleotides," Nucleic Acids Research, Vol. 11, pgs. 6513-6529(1983), disclose a method for attaching amines to the terminal 5'-phosphates of oligonucleotides. One object of the method is to provide a means for attaching organic labeling molecules to oligonucleotides by way of an amine linkage. The method involves treating the oligonucleotides with a carbodiimide.
Chollet and Kawashima, in "Biotin-Labeled Synthetic Oligodeoxyribonucleotides: Chemical Synthesis and Uses as Hybridization Probes," Nucleic Acids Research, Vol. 13, pgs. 1529-1541 (1985), disclose the use of the method of Chu et al to attach biotin to the 5'-phosphate of an oligonucleotide. The reported yields of 50-70% are below that needed for use in automatic synthesizers, and the carbodiimide can cause unwanted modifications to oligonucleotide bases in the course of the reaction.
Smith et al, in "Synthesis of Oligonucleotides Containing an Aliphatic Amino Group at the 5' Terminus: Synthesis of Fluorescent DNA Primers for Use in DNA Sequence Analysis," Nucleic Acids Research, Vol. 13, pgs. 2399-2412 (1985), disclose a protected amino-derivatized nucleoside phosphoramidite for linking fluorescent or colorimetric tags to oligonucleotide fragments. While the linker is highly useful for attaching base-specific labels to the 5' terminus of oligonucleotides, the protected-amine phosphoramidite is not readily purified.
Connolly and Rider, in "Chemical Synthesis of Oligonucleotides Containing a Free Sulphydryl Group and Subsequent Attachment of Thiol Specific Probes," Nucleic Acids Research, Vol. 13, pgs. 4485-4502 (1985), disclose the synthesis of oligonucleotides having a trityl-protected sulphur attached via a two, three, or six carbon chain to the 5' phosphate of the oligonucleotide.
Apart from linking labeling agents to oligonucleotides, there is great interest in immobilizing various molecules on polymer supports, such as catalysts, enzymes, microorganisms, affinity reagents, immunoadsorbents, and the like, for both preparative and analytical uses, e.g. Schott, Affinity Chromatography (Marcel Dekker, Inc., New York, 1984), and Mosbach, ed., Methods in Enzymology, Vol. 44, "Immobilized Enzymes," (Academic Press, New York, 1976). Of particular interest in this field are means for immobilizing molecules and cells by covalent bonds.